Resonance - what happens when a 3-phase line reactor meets a 3-phase capacitor?

[bdn2004]

The phenomena of resonance...I read where if there is added capacitance in a circuit - to not use line reactors because of it.
What happens, what could happen? When would it be a concern and how do you calculate it?

Given:

170 FLA load, unknown capacitance of the load.
0.13 mH Line Reactor, calculated impedance: 0.047 ohms / phase
480V

 

[HamburgerHelper]

If you have a resonant condition, you will have large currents. At the point of resonance, the voltage will get very high in between the reactor and the capacitor. If Xc = Xl, the current will be very high (V/(j*Xl-j*Xc)) on this path and the voltage that develops between the reactor and the capacitor will be, I*Xc or I*Xl, and this will be higher than your source voltage.

When I did a study for a harmonic filter, I modeled the system and did a frequency scan and designed the filter to handle the harmonic currents that were being injected by a VFD.

The IEEE-399 the Brown book has a section that talks about how to do harmonic studies.

https://ieeexplore.ieee.org/document/18478

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If you can't explain it to a six year old, you don't understand it yourself.

 

[beyond86]

I think you should distinguish a series resonant and a parallel resonant.

 

[RRaghunath]

Is the reactor Air-cored or Iron-cored!
The reactance of iron core reactor will decrease whenever there is voltage excursion.
At some point, when the inductive reactance equates the capacitive reactance, resonance occurs that could cause destruction due to high currents or voltages.

Rompicherla Raghunath

 

[bdn2004]

It’s an iron core reactor installed in series with the incoming cabling to an industrial control panel. The loads inside the panel are in parallel I’m assuming. I’m not sure right now if there are capacitors installed and why there would be - but this is a sophisticated specially made machine. Can the capacitance of such a machine be measured?